Pneumatic barrier system for water surfaces

ABSTRACT

A system for the confinement of pollutants on water surfaces until collected or chemically dispersed. The system effects its confining action by generating a curtain or barrier of air bubbles which at the surface of the water form a series of overlapping aerated water hills capable of blocking the passage of a pollutant, such as oil film, therethrough. The system is designed to enable it to provide a continuous barrier of aerated water hills over long period of use and even though it may be installed on harbor and waterway bottoms where silty conditions prevail. This is accomplished by a pipe for supplying compressed gas to an outlet comprising a nozzle plate having an orifice of a size to allow a metered amount of air to pass with a check valve located downstream of the nozzle plate.

United States Patent Grimaii [451 Feb. 28, 1972 [54] PNEUMATIC BARRIERSYSTEM FOR 21 Appl. No.1 39,262

Primary Examiner-S. Leon Bashore Assistant Examiner-Robert L. Lindsay,.lr. Attorney-Sylvester J. Liddy, John J. Hart, Joe E. Daniels andCharles E. Baxley [57] ABSTRACT A system for the confinement ofpollutants on water surfaces until collected or chemically dispersed.The system effects its confining action by generating a curtain orbarrier of air bubbles which at the surface of the water form a seriesof overlapping aerated water hills capable of blocking the passage of apollutant, such as oil film, therethrough. The system is designed toenable it to provide a continuous barrier of aerated water hills overlong period of use and even though it may be installed on harbor andwaterway bottoms where silty conditions prevail. This is accomplished bya pipe for supplying compressed gas to an outlet comprising a nozzleplate having an orifice of a size to allow a meteredv amount of air topass with a check valve located downstream of the nozzle plate.

3 Claims, 7 Drawing Figures PTA'TENTEU MR 2 8 1972 FIG.

INVEN'I'ORv HE/NZ GEU/VAZ/ BY rival/2 A T TORNE 7 1 PNEUMATIC BARRIERSYSTEM FOR: WATER SURFACES THE INVENTION The primary object of thepresent invention is to provide an improved pneumatic barrier for watersurface pollutants that is capable of effectively accomplishing thepurposes for which it was installed even after periods of disuse in adifficult environment. Areas of water polluted with oil or othercontaminant filrns have been isolated to prevent the spread of suchfilms and to effect their removal by creating below the surface of thewater an air bubble barrier or curtain. When the air bubbles in suchbarrier rise to the water surface they form a series of over-Iappingaerated water bills capable of preventing passage of a filrnacross the pneumatic barrier so created. Such a barrier maybe created byarranging an air conduit having a series of openings or orificesunderwater in a manner to provide the form of the barrier which will bemost effective in accomplishing the confinement of the pollutant in aparticular situation. Air is supplied to the conduit under pressure inany suitable manner and is usually kept flowing through the conduit tomaintain the pneumatic barrier until the oil film confined or retainedhas been collected from the surface of the water or has been chemicallydispersed. This process ,of collection or dispersion may require hoursor days to accomplish depending on the volume of the film and theconditions encountered.

When the film has been collected or dispersed, the pneumatic barrier isdeactivated, i.e., the compressed air supply to the conduit is shut off.When this is done, any air remaining in the conduit escapes through theopenings or orifices thereof. As the pressure of the water around theconduit becomes greater than the air pressure within the conduit, waterwill flow through some of the conduit openings and into the conduit. Most waterways and harbors contain at or near their bottoms, deposits oforganic silt, finely divided clays, sands or sandy gravels, which form asuspension of finely divided particles. Consequently, when water flowsthrough the openings or orifices of a conduit located in or near such anenvironment, it tends to carry such finely divided solids with it. It isthus necessary when compressed air is readmitted to the conduit toreestablish the pneumatic barrier to blow out the water and solidsdeposited within the conduit by use of an air pressure which is greaterthan the hydrostatic pressure of the water on the conduit. It has beenfound that the solid particles carried into the conduit upondeactivation of the pneumatic barrier, tend to settle and consolidatewithin the confined area of the conduit; and that upon readmission ofcompressed air into the conduit, the interaction of the turbulent flowof the compressed air displacing the water and settled particles withinthe conduit, causes such solid particles to plug the openings ororifices from within. When one or more orifices are partially orcompletely plugged, air cannot be emitted at the calculated rate to formthe proper aerated water hills for confinement of the film, and thecontinuity of such water hills will be destroyed. Wherever thecontinuity of such water hills is so disrupted, thefil'm will tendtoes'cape thus rendering the barrier incapable of accomplishing itsintended purpose.

The aforesaid objection of systems of theindicated type is overcome bythe improved system hereinafter described and illustrated in theaccompanying drawings,'in which FIG. 1 is a schematic sectional viewshowing by way of example a portion of a harbor basin provided with abarrier embodying the invention;

FIG. 2 is a vertical sectional view taken along the line 2-2 In thedrawings, the numeral 10 indicates generally a harbor basin bordered onone side with a quay wall 11 and having a harbor bed 12 on which is adeposit 13 of organic silt, finely divided clay or the like. Laid on thedeposit 13 is a conduit I4 composed of a plurality of conduit sectionsor lengths 14 connected together by couplings IS. The conduit 14 is laidin a manner to isolate the area occupied by the oil or other contaminantfilm to be confined and removed. Thus, the conduit 14 may extend acrossthe basin 10, or may be given any desired form on the harbor bed 12 toeffect the intended confinement of the oil film. The conduit 14 isconnected at one end by a section 16 to an air compressor 17 mounted onthe quay wall 11. It will be understood that if an oil film on an openarea of water is to be contained, the air compressor 17 will be mountedon a vessel and the connecting conduit 16 is preferably flexible. Itwill also be understood that instead of laying the conduit on the bed orfloor of the water area in which the oil film is located, suchconduitmay be supported in suspended relation from surface floats.

The sections of conduit 14 may be made of any suitable material such assteel, cast iron, rubber or synthetic rubber,

. plastic, etc., and preferably has a relatively thick wall. In the ductsections 14' illustrated, the wall thickness is of the order ofapproximately one-half inch. Provided along the upper edge portion ofeach section 14' is a longitudinally extending series of spaced airnozzles generally designated 20 in FIGS. 1 and 2. The nozzles 20 arespaced apart a distance such that when the columns 21 of air bubblesarising therefrom reach the water surface they form a series ofoverlapping aerated water hills 22 which provide a continuous band orbarrier having a configuration corresponding to the manner in which theconduit 14 is laid on the water floor 12. These hills 22 well outtransversely on either side of their alignment and prevent the oil filmfrom passing through the pneumatic barrier.

As is shown more clearly in FIGS. 2-7 of the drawings, each nozzle 20 iscomposed of a nozzle body 25 having a length approximating the thicknessof the conduit wall and made of any suitable material such as plastic,metal, or synthetic rubber compound. The nozzle body is provided with anexternal screw thread 25 which threadedly engages a matching internalscrew thread 27 provided in the wall of its associated opening in theconduit section 14'. The head 28 of the nozzle body is provided withslots 29 for receiving the tool used to screw the nozzle body 25 intoposition on the conduit section. Spaced approximately three-quarters ofthe length of the nozzle body from the head end thereof is an internalannular groove 30 in which is seated an external flange 31 provided onthe lower end of a tongue sealed check valve 32. The valve 32 has aheight less than the height of the nozzle body 25 above the groove 30thereof so that it is entirely contained within such body. The tongueslit or resilient flaps 33 at the top of the check valve 32, the body ofsuch valve and the flange 31 thereof are made of an integral piece ofrubber or other suitable material. The rubber check valve 32 ispreferably inserted into the nozzle body 25 through the bottom of thelatter until the valve flange 31 is engaged in the nozzle body groove30. The check valve is then locked in position by a nozzle plate 35provided with an 'extemal screw thread 36 which is in threadedengagement with a matching internal screw thread 37 provided in thebottom end of the nozzle body below the groove 30 thereof. The nozzleplate 35 is provided with an orifice 38 through which air escapes fromthe conduit. It will be understood that the nozzles 20 are eachcompletely assembled as aforesaid before being screwed into the internalthreads 27 provided in the conduit openings.

It will be understood from the foregoing, that when the system is inoperation compressed air supplied to the conduit 14 from the aircompressor 17 escapes at each nozzle 20 in the conduit. The air escapingat each nozzle 20 initially passes through the orifice opening 38 in thenozzle plate 36 thereof. The opening 38 is of a predetermined diameterand controls the volume of air being emitted by the'nozzle. 'Thecompressed air emitted through orifice38 passes through the body of thecheck valve 32 and due to its excess of pressure over the hydrostaticpressure, forces apart the tongue slot 33 at the top of such body, andthence forms the bubbles which rise in a column 21 through the water andproduce the water hills 22 at the water surface. When the compressed airsupply is shut off, pressure within the conduit is equalized to thehydrostatic pressure by escape of air through the nozzles, and furtherreduced by cooling of the air within the conduit. When the hydrostaticpressure exceeds the internal pressure at the valve tops 33 of thenozzles, this pressure closes the tongue slots, thereby preventing theflow of water and solid particles back into the conduit. The hydrostaticpressure also forces the check valve flanges 31 against the inner sidesof the body grooves 30 and the upper ends of the joints between thethreads 36, 37 thereby sealing the nozzles 20 completely against theinflow of the solid particles in suspension therethrough and into theconduit 14.

What is claimed is:

l. A pneumatic barrier system for forming on the surface of a body ofwater a pollutant confining water barrier constituted of overlappingaerated water hills, comprising an underwater conduit arrangeable in agiven geometric pattern defining the area of the water surface withinwhich the pollutants are to be confined and having a plurality of airescapement openings located in given spaced relation along the lengththereof, means associated with said openings for controlling theejection of air from said conduit and the reception of solid particlesinto said conduit on the cessation of such air ejection, and means forsupplying compressed air to said conduit for escapement through saidcontrol means against the hydrostatic pressure, said control means ateach conduit opening ineluding relatively rigid means substantiallyblocking the passage of air through the conduit opening and beingprovided with a reduced orifice of constant given dimensions throughwhich is ejected a precise flow of pressurized air capable of forming atthe water surface an aerated water hill, and said control meansincluding a tubular member for conducting the flow of air dischargedthrough said reduced orifice to the body of water, said tubular memberhaving an interior diameter substantially greater than said reducedorifice and having at its discharge end resilient flaps that arerelatively freely spreadable by the pressurized air flow from saidorifice to permit the ejection thereof and that close automatically whenthe hydrostatic pressure exceeds the air pressure in said tubular memberto prevent the reception through said tubular member and orifice andinto said conduit of solid particles in suspension in the body of water.

2. A system as defined in claim 1, in which said rigid means is a platehaving a centrally located reduced orifice, and in which said tubularmember is seated at its inner end in sealed relation on the periphery ofthe outer face of said plate.

3. A system as defined in claim 2, in which said control means comprisesa tubular housing having an external thread in threaded engagement withthe wall of the conduit opening, an internal thread in its inner portionand an inner annular seat adjacent the outer end of said internalthread, said tubular member having at its inner end an external flangemounted in said annular seat and on the periphery of said plate, andmeans engageable with said internal thread and sealing said externalflange to the periphery of the outer face of said plate.

1. A pneumatic barrier system for forming on the surface of a body ofwater a pollutant confining water barrier constituted of overlappingaerated water hills, comprising an underwater conduit arrangeable in agiven geometric pattern defining the area of the water surface withinwhich the pollutants are to be confined and having a plurality of airescapement openings located in given spaced relation along the lengththereof, means associated with said openings for controlling theejection of air from said conduit and the reception of solid particlesinto said conduit on the cessation of such air ejection, and means forsupplying compressed air to said conduit for escapement through saidcontrol means against the hydrostatic pressure, said control means ateach conduit opening including relatively rigid means substantiallyblocking the passage of air through the conduit opening and beingprovided with a reduced orifice of constant given dimensions throughwhich is ejected a precise flow of pressurized air capable of forming atThe water surface an aerated water hill, and said control meansincluding a tubular member for conducting the flow of air dischargedthrough said reduced orifice to the body of water, said tubular memberhaving an interior diameter substantially greater than said reducedorifice and having at its discharge end resilient flaps that arerelatively freely spreadable by the pressurized air flow from saidorifice to permit the ejection thereof and that close automatically whenthe hydrostatic pressure exceeds the air pressure in said tubular memberto prevent the reception through said tubular member and orifice andinto said conduit of solid particles in suspension in the body of water.2. A system as defined in claim 1, in which said rigid means is a platehaving a centrally located reduced orifice, and in which said tubularmember is seated at its inner end in sealed relation on the periphery ofthe outer face of said plate.
 3. A system as defined in claim 2, inwhich said control means comprises a tubular housing having an externalthread in threaded engagement with the wall of the conduit opening, aninternal thread in its inner portion and an inner annular seat adjacentthe outer end of said internal thread, said tubular member having at itsinner end an external flange mounted in said annular seat and on theperiphery of said plate, and means engageable with said internal threadand sealing said external flange to the periphery of the outer face ofsaid plate.